Many custom enforcement personnel employ dogs to detect dangerous or illegal materials, chemical materials and biological materials by the odors emitted thereby. Also, odors emitted from the body of a living subject (human or animal) may provide indications about the physiological or mental state of a subject, such as early stages of cancer, an incubation stage of an epidemic etc. Therefore, fast and reliable detection of such emitted odors is highly desirable.
Trained dogs are generally among the most reliable means for detecting such materials, being able to detect target odors at extremely low concentrations in the order of 1 part per million or less. Trained dogs have been used in field for detecting explosive materials, more than any other methods, since the nose of a dog is the most advanced sensor provided by evolution, much more advanced than any other technology. Actually, there is no such accurate, fast, sensitive, mobile and durable technology that can meet the capabilities of a trained dog. Some canine based detection systems are disclosed for example in U.S. Pat. No. 7,717,066, US 2009/0038555, and FR 2956211.
However, prior art canine based detection systems suffer from several disadvantages. Firstly, the handler must have high skills in order to accurately identify and interpret the dog's behavior, as well as changes in its behavior.
Generally, it is hard for a dog to detect a target odor alone and it needs to operate in conjunction with a handler. The quality of odor detection of a trained dog is determined by the skills of its handler.
Secondly, the screening process preceding a detection event is relatively long and monotonic to the handler and it is hard for him to maintain a high level of motivation and awareness for long periods. As a result, when the dog feels that the motivation of his handler has been deteriorated, it will not perform his part appropriately.
Thirdly, using conventional detection methods and devices cause the capability of a dog to operate efficiently to be limited to continuous periods of up to 20 minutes in good weather conditions and even less in worse weather conditions. Generally, the average total net operation period of a dog is limited ranges between 60-180 minutes for each 24-hour period. Therefore, the output obtained from a trained dog is relatively low, due to its level of fatigue and whether conditions. The aforementioned disadvantages of the prior art canine based detection systems may be obviated when the dog performs an odor detection operation within a compartment which is partially of fully isolated from its handler and target material. It should be mentioned that dogs have natural tendency to freedom and natural hesitation from confined compartments and places. Forcing an untrained dog to enter such a confined compartment will cause it to try getting out from the compartment to be free, while trying to bite and scratch the walls of the compartment.
U.S. Pat. No. 7,921,810 discloses a method for detecting a target substance by training an animal to execute a particular avoidance action upon detecting a target substance in order to avoid an aversive stimulus such as an electric shock, a loud noise, and a bright light. In an operational phase, the trained animal is exposed to air flowing through a container containing a specimen odor to be examined. Sensors produce a useful output signal when the trained animal performs the avoidance action. The animal is housed within a cage that includes the basic living necessities for the animal during the training phase and the operational phase.
By being subjected to an aversive stimulus, the trained animals are caused to be under constant psychological stress due to the concern that they will again be subjected to an irritating negative reinforcement. As a result of the psychological stress to which the animal is subjected, it may refuse to enter a confined compartment and to accurately perform long-duration detection of target odors.
It is an object of the present invention to provide an apparatus and method for training a dog to willingly enter a confined compartment and to consequently perform accurate and long-duration odor detection operations, while keeping the energy and high performance of the dog for longer time periods.
Other objects and advantages of the invention will become apparent as the description proceeds.